New Diabetes Drug Linked to Breast, Bladder Cancer

Bristol-Myers Squibb and AstraZenecaâ€™s joint diabetes effort, the pill dapagliflozin, although successful in a two-year study, might be linked to bladder and breast cancer, according to the U.S. Food and Drug Administration (FDA).

Medical News Today said the agency is still deciding on whether or not to approve dapagliflozin and is expected to make its final decision by month-end, October 2011. Market experts believe the FDA could ask for additional proof of dapagliflozin’s efficacy before it makes its final decision, added Medical News Today.

According to clinical trials, more cases of breast and bladder cancers were seen in dapagliflozin patients than those on a placebo, with 9 cases each of bladder cancer and breast cancer in dapagliflozin patients versus 1 each in the placebo, said Medical News Today, citing the clinical trials. Also, the FDA stated that dapagliflozin does not work as well in diabetics who also have impaired kidney function; liver injury, bone safety, and urinary and genital infections were also cited.

The reviewers wrote, quoted Medical News Today that, “Several unexpected safety issues identified in this clinical development program were of sufficient concern to FDA to merit discussion of their impact on the overall benefit-risk consideration of dapagliflozin.”

Dapagliflozin is likely the first drug in an emerging diabetes drug class to block glucose absorption into the bloodstream via the kidneys, said Reuters. This process will enable greater amounts of sugar to excrete via urine; however, this is might be linked to the increased cancer risk. Because dapagliflozin leaves more sugar in the urine, it could be acting as a bacterial and pathogenic nutrient, which could lead to infections, said Elisabeth Svanberg, vice president of development for dapagliflozin at Bristol-Myers, wrote Reuters previously.

Weâ€™ve also been following the issue of Actos, a drug approved for the treatment of Type 2 diabetes, and its links to increased bladder cancer, which prompted a few medical societies to speak out. The Endocrine Society, American Association of Clinical Endocrinologists, and American Diabetes Association urge patients with diabetes to remain on their prescribed medications unless told to discontinue that medication on the advice of their physicians and also say that patients follow FDA guidance, which advised that, when taking Actos, there is the potential for increased risk of bladder cancer and that patients should not take this medication if receiving bladder cancer treatment. In response to concerns that the drugâ€™s risks outweigh its benefits, Actos is being pulled from the French market.

Also, by November, the diabetes drug Avandia (rosiglitazone) will no longer be available in U.S. retail pharmacies. Patients who are prescribed Avandia will only be able to obtain the controversial medication from selected certified pharmacies via mail order, the FDA recently announced. Both doctors and patients will have to meet additional requirements if they want to use Avandia. The severe restriction is being put in place over heart risks. The FDA actually decided to restrict sales of Avandia last year, after concluding its risks outweighed its benefits; however, the agency only just announced how the new rules would be implemented.